Re: Repairing the key on 147/156
I think it's safe to say that some keys MAY be much harder to open than others. Your first picture Kurzon is the same as my key and it was stuck slightly at one end.
It is probable that different suppliers produced the key for Alfa and who knows, some may have been stuck and others not. One weakness is that the keyring adaptor can pop out - to stop this you would glue the key together especially at that end.
So I think it's best to say that some keys will come apart easily and others won't so go carefully and patiently.